Advice from the oldest ever Olympic marathon winner Romania's Constantina Dita, who took gold aged 38 at Beijing in 2008
1. GET SPEEDY: 'Marathoners often focus on getting in the miles, but you also need to do tempo and interval runs to get faster. Taper off the intensity in the two weeks before race day,' says Constantina.
2. EAT WELL: 'If your mineral levels drop low, you're likely to get muscle cramps. Eat plenty of fruit, veg, fish, chicken and beef.'
3. RUN NEGATIVE SPLITS: 'Run the second half faster than the first. My plan at Beijing was always to stay slow for the first half, then race away.'
